The present invention relates to a centrifugal pump particularly suitable for use with washing machines, dishwashers or other similar household appliances which provide liquid discharge operating cycles.
Centrifugal pumps of the known kind, usually employed in household appliances such as dishwashers and washing machines, are generally composed of an asynchronous motor combined with a centrifugal pump the impeller of which is positioned in a sealed chamber.
In practice the axle of the electric motor enters the pump body with the interposition of an annular or toroidal liquid seal which prevents the liquid from flowing out.
This seal represents one of the most critical points of the motor-to-pump coupling and the leakage of liquid through this seal is one of the most frequently occurring and damaging failures, as it usually results in the electric motor being damaged.
It should be further considered that the pump, particularly if installed in washing machines for domestic use, is affected by a liquid which carries in suspension sand and dust which produce a damaging abrasive effect, especially on the seals in the moving parts, and fiberous matter which by twisting around the impeller and the axle of the pump cause remarkable inconveniences which may even entail the jamming of the pump itself.
The problem of a jammed pump in a household appliance is not a minor one because, additionally to blocking the machine, it requires the intervention of highly specialized personnel also because of the notable complexity due to the hydraulic sealing and centering means themselves.
Also from a production standpoint, the making of asynchronous motors and their subsequent association with pumps of the centrifugal kind, having a separate structure, turns out to be particularly expensive and may imply very difficult assembly.